Process of recovering salts from admixtures thereof in solution.



E.N.TRUMP. PROCESS OF RECOVERING SALTS FROM ADMIXTURES THEREOF IN SOLUTION.

APPLiCATlON FILED MAR. 24,1916. 1 6,18? Patented Feb. 13, 1917.

\lillll (QM n. lwp, @Hozucu; afar/W1 acLuM;

on snare Parana onnrcn.

EDWARD 1\T. TRUMP, OF SYRACUSE, NEW YORK, ASSIGNOE TO THE SOLVAY PROCESS COMPANY, OF SOLVAY, NEW YORK, A CORPORATION OF NEW YORK.

PROCESS OF RECOVERIN G SALTS FROM ADMIXTURES THEREOF IN SOLUTION.

11,216,18't. i Specification of Letters Patent Patented Feb. 113, 191i 7.

' Application filed March 24, 1916. Serial No. 86,394.

To all 107mm it may concern: centration in salts thereby increased. In Be it known thatI, EDWARD N. TRUMP, a the case of effect, D, it is necessary, in order citizen of the United States, residing at to effect circulation of the solution, to also 55 Syracuse, in the county of Onondaga and close valve,'8, located in pipe, 9, which leads State of New York, have invented a new from pipe, f, to the filter, or centrifugal and Improved Process of Recovering Salts separatonF. By closing the valves, 4:, and from Admixtures Thereof in Solution, of opening the valves, 6. and 7, which are in which the following isa specification. terposed in the pipe, f, between each two 60 y invention relates particularly to the eifects, and valves, 5, the pumps, P, oper- 10 separate recovery from a solution of two ate to force the solution from the lower or more salts, such, 6. 9., as sodium sulfate part of each effect, together with the salts and potassium chlorid, which have soluhiliprecipitated therein, through the pipe, 7, to

. ties differently varying according to the the efi ect having the next higher tempera- 65 temperature of the solution, and the object ture, as from effect, D, to effect, C,'and effect,

ofcmy improvements is to provide a .co ntin- C, to effect, B, and from'elfect, B, to effect, A. u'ous, methodical and efficient method of ef- From effect, A, upon opening valves, 5 and 7, fecting such separation. valve, 4:, being closed, the salt, together with e The invention will be best understood by the solution, in the lower portion thereof is 70 describing it in connection with the accomforced by pump, P, through pipe, h, to

panying drawing which is a diagrammatic a filter or centrifugal separator, F, where illustration of a'multiple effect evaporating the salt is separated from the mother liquor. apparatus suitably arranged for carrying By partially opening valve, 4, a portion it into elfect. The evaporating apparatus, of the liquor will be circulated through the 75 "as shown, consists of four effects of usual adjoining eflect while another portion will construction indicated as A, B, C, D. The be forced into the next higher-effect so that concentration of the salt conta-ining solw the operations of circulating the liquor to tion is effected in the usual manner, effect increase concentration and of transferring A being heated by the steam entering it by the precipitated salt from effect to eifect will 80 pipe, a, effect, B, being heated by the steam be performed at the same time.

generated in effect, a, and so on to the end It will be understood that the tempera; of the series, the steamformed in efiect, D, ture of the solution is highest in eifect, A,

passing to a condenser, E. q and decreases through the several effects, The solution from-which the salts are t0 being lowest in effect, D. be recovered is admitted in the first instance At the temperatures maintained that salt,

from a feed tank, T, through pipe, I), to as potassium chlorid, which decreases in, effect, A. From effect, A, the solution consolubility with decrease oftemperature, will centrated by evaporation in each effect in the first instance precipitate mainly in the passes in succession by pipes, c, d, and 6, lower portion of effect, D, while that salt, 90 to effects, B, C, and D. In each case the as sodium sulfate, which decreases in solu- 40 solution is taken out of the effect at a point bility with increase of temperature will prewhere the solution is relatively free from cipitate in effect, A, as well as in the other precipitated salts and enters the succeeding elfe'cts. effect throughpip'e, 7, which connects the As the mixed salts are transferred 95 lower portions of the several effectsin which through the operation of pumps, .1, through the salts formed are, in the first instance, pipe, f, through effects, C, and B, and past precipitated. the inlets of pipes, c and (Z, to pipe, f, they In connection with each elfect is a pump, are brought into contactwith unsaturated P, whereby (except in the case of efieetD). liquor of progressively increasing temper- 100 upon opening valves, 4, and 5, and closing ature in each successive effect so that the valves, 6 and 7, on either side of the effect, more soluble salt will be dissolved out, and, the solution can be circulated atwill through in effect, A, there will be found only the thelower portion of each efiect and its eonsalt which has less solubility at the higher n w; I amas:

temperature. This is removed from the mother liquor in the filter or centrifugal, F. The mother liquor, carrying in solution the more soluble salt, passes from the centrifugal, F, through pipe, 6, and is added to the incoming fresh liquor and again enters the system ofefl'ects through pipe, I), so that the solution in the effects becomes more concentrated in the more soluble salt.

It will be evident that the operation may be continued to a point at which the concen tration of the more soluble salt in the solution will be such that this salt will be precipitated at the highest temperature in effect, A. Just before this point of concentration is reached, however, valves, 4 and 7, in pipe 1, on either side of pipe, 9, are closed and valve, 8, in pipe, g, is opened and by the operation of pump, P, adjacent to effect, D, the more soluble salt in effect, D, is forced into the filter or centrifugal, F. In this manner the concentration of the liquor in the more soluble salt is reduced below the pointat which its precipitation at the high temperature is possible and this salt is recovered at its maximum degree of purity and largely separated from the less soluble salt.

The mother liquor from the centrifugal," F", is carried back to the system through pipe, is, for the recovery of any contained salts.

In this manner by continuously transferring the precipitated salts in the direction of the effect of highest temperature, from which the least soluble salt is removed, while maintaining such a temperature that the more soluble salt will not normally be precipitated therein and thus dissolving the more soluble salt formed, and at the same time concentrating the solution in the more soluble salt and transferring the concentrated solution in the opposite direction and periodically removing the precipitate of the more soluble salt from the effect of lowest temperature when the solution has reached the proper point of concentration therein, an efficient separation of the salts is effected.

What I claim as new and desire to secure by Letters Patent is:

1. The process of separately recovering salts from admixtures thereof in solution, which consists in concentrating the solution in a multiple effect evaporator, transferring the solution from the efiect of highest tern: perature through the several effects to the effect of lowest temperature and transferring the precipitated salts through the several efiects to" the effect of highest temperature whereby the more soluble salt is dissolved, and removing the salts at the opposite ends of the series of effects. 2. The process of separately recovering salts from admixtures thereof in solution which consists in concentrating the solution in a multiple effect evaporator, transferring the solution through the several effects in one direction and transferring the precipitated salts through the several effects in the opposite direction, whereby the more soluble salt is dissolved, and removing the precipitated salts separately at the opposite ends of the series of effects.

3. The process of separately recovering salts from admixtures thereof in solution which consists in evaporatingthe solution in a multiple eflect evaporator, transferring the solution through the several effects from the effect ofhighest temperatureto the effect of lowest temperature, transferring the precipitated salts through the several effects in the opposite direction, washin the salts in solution of progressively hig er temperature and thereby dissolving the more. soluble salt, removing the less soluble salt'from the effect of highest temperature and returning the mother liquor to the effects. and. periodically removing the more soluble salt from the effect of lowest temperature while' its solution concentration is. such that it will not precipitate in the efiect of highest tem'- perature. v

In testimony whereof I hereto aflix my signature, this 22nd day of March, 1916.

EDWARD N. TRUMP. 

